Fitian Charger Cable Connector Charging Cord for Microsoft Surface Pro 3 12 Inch/Pro 4 Inch 12.3 Tablet to 12V DC Power Bank External Battery (Magnetic, 5.5x2.1mm) Special designed for Microsoft surface pro 3 12 inch/ pro4 inch 12.3 tablet A convenient backup charging cable for travel and business Cable length: About 3.9~4.9 feet Note: Be sure Compatible with most 12V power supply with a 5.5x2.1mm DC male connector.to set powergrid travel charger to 12V when connecting the cable to your Micro Surface Pro 3/Pro 4 Note: The extra male to female connector and power bank in the picture is NOT included in the package. Just for reference.